BigQuery is designed for large-scale analytics (OLAP), not high-speed transactional processing (OLTP) like PostgreSQL. BigQuery is less suitable for frequent row-level inserts, updates, deletes, and real-time transactional workloads because queries have higher latency and limited transaction handling compared to PostgreSQL. It also lacks features commonly needed in OLTP systems, such as fine-grained indexing, complex row-level locking, and ultra-low-latency operations, making it better for reporting and analytics rather than application back-end transactions.